AIM: Trigonelline is a potent phytochemical present in fenugreek, which has strong anti-oxidant and phytoestrogenic activities. This study was carried out to investigate this estrogenic activity as a possible mechanisms involved in preventing the symptoms of osteoporosis in dexamethasone induced osteoporosis in rats. MATERIALS AND METHODS: Wistar rats were randomly divided into eight groups, six animals in each group. Osteoporosis was induced using dexamethasone 0.1mg/kg subcutaneously in rats for three times per week for 8 consecutive weeks and treatment with drugs up to 12 weeks as per the treatment schedule described. After 12 weeks, rats were sacrificed; blood samples were collected from each rat and the clear, non hemolysed supernatant sera was used for biochemical examinations. Femurs were used for Bone Mineral Density (BMD), microcomputed tomography (Micro CT), histology and biochemical examinations. RESULTS: BMD, bone micro structure, serum calcium, phosphorus level and serum estradiol levels were decreased while serum PTH levels, SAP and acid phosphatase (ACP) were elevated in dexamethasone treated rats as compared to control (p<0.01). Dexmethasone treated animals showed loss of marrow at multifocal area, cartilage and trabeculae and thinning of trabeculae (bone resorption), zone of cartilage was poorly seen and fat cells in marrow. Trigonelline showed significant improvement and prevent the progression of osteoporosis by enhancing the BMD, restoring bone physiology. CONCLUSION: Our results confirm the estrogenic activity of triogonelline, which is responsible for its effects; still, it needs further evaluation in other animal models to provide a more conclusive view for its therapeutic usefulness in osteoporosis. CI - (c) Georg Thieme Verlag KG Stuttgart . New York.